fix: GUI max-width on wrapper + visible TTS swap result + warning cleanup

GUI MAX-WIDTH (was still stretched)

Root cause v2: my earlier rule applied max-width to #header and main
INDIVIDUALLY, but they live inside <Container fluid id="wrapper"> from
svelteui which goes full viewport width. Both children inherited that
full width from the flex layout. Constraining each child wouldn't help
when their PARENT was unconstrained.

Fix: max-width:1280px !important on #wrapper itself, with margin:0 auto.
Now the whole app (header + main) sits in a centred 1280px column on
wide monitors. !important is unfortunate but Container's width:100%
sometimes wins under HMR otherwise.

VISIBLE TTS SWAP RESULT (was failing silently)

User saved 'Piper' in dropdown → green 'Saved!' banner → active engine
chip still showed 'sapi'. Root cause: when Piper isn't installed,
`tts::build_backend("piper")` falls back to SAPI internally, but
`set_tts_backend` just logged a warning and returned a generic string.
The GUI couldn't tell the difference between success and silent fallback.

Fix:
- `set_tts_backend` now returns `TtsSwapResult { requested, applied,
  fell_back, note }`. The Svelte page reads `applied` (actual installed
  backend), checks `fell_back`, and shows an ORANGE notification with
  the concrete fix ("запусти tools/piper/install.ps1 чтобы скачать
  бинарь") instead of a green 'saved' lie.
- Saves now also call `refreshActiveBackends()` so the live chip
  ("Активный движок: TTS: sapi") updates without page reload.
- Green notification when swap succeeded normally.

WARNING CLEANUP

- jarvis-app/main.rs: removed unreachable `_ => {}` arm (all IpcAction
  variants are explicit now).
- jarvis-app/tray.rs: moved `info!("Tray initialized.")` to BEFORE the
  Windows message-pump loop (the loop runs forever, so the original
  position was unreachable).
- jarvis-gui/main.rs: dropped unused #[macro_use] on simple_log.
- jarvis-gui/events.rs: #[allow(dead_code)] on Payload struct +
  EventTypes impl + `play` fn — they're intentional API surface for
  future event-emitter wiring, not actual dead code.
- Plus a `cargo fix` pass for misc unused imports.

Down from 12 warnings to 1 (npm-build-completion notice — informational).

Tests: 140 rust + 115 python (was 104, +11 for new wave59_handlers).
Release builds of jarvis-app + jarvis-gui both green.

crates/jarvis-core/src/i18n.rs

@@ -1,4 +1,4 @@
-use fluent_bundle::{FluentBundle, FluentResource, FluentArgs, FluentValue};
+use fluent_bundle::{FluentResource, FluentArgs, FluentValue};
 use fluent_bundle::concurrent::FluentBundle as ConcurrentFluentBundle;
 use once_cell::sync::OnceCell;
 use parking_lot::RwLock;

crates/jarvis-core/src/llm/history.rs

@@ -1,6 +1,6 @@
 use super::client::ChatMessage;
 use std::fs;
-use std::path::{Path, PathBuf};
+use std::path::PathBuf;
 
 pub struct ConversationHistory {
     system: Option<ChatMessage>,